This invention relates in general to load stabilizing apparatus and more particularly to a means for axially supporting a canisterized missile, while at the same time allowing the missile to translate in any radial direction relative to the canister tube when subjected to seismic forces caused by an earthquake or nuclear ground shock.
Typically a longitudinal support assembly for a missile is required to provide acceptable static and dynamic stability compliance in the axial, lateral, and roll orientations with respect to the missile axis, without overloading the missile. These requirements are expressed in terms of axial, lateral, torsional, and bending stiffness; and missile allowable loads.
Various design approaches have been heretofore utilized to fulfill the aforementioned requirements and constraints. For example, elastomer sandwiches have been configured so that with rods piercing them they produce compression modes and allow for bi-axial motion. The correct spring rates in all the modes have been obtained.
Another approach has been to tailor longitudinal rod elements to relatively stiff axial stiffnesses while allowing much lower spring rate lateral motions. The end connections (fixed or pivoted or a combination thereof) on these elements determine the degree of torsional stability available.
As the specific combinations of lateral and axial stiffnesses have changed, either with a basing mode change or through refinements of shock definition, such composite design approaches which satisfy all of the aforementioned requirements have been less successful. The use of decoupled elements, each of which address a separate stability requirement, has been a better approach to these more demanding situations. For example, axial rod elements have been designed which alternately provide the required axial stiffness and lateral stiffness. A bellows structure has been added in parallel with the rods where spherical bearings terminate the rod ends.
The additional complexity, cost and potential interactive modes however, have made these decoupled approaches less attractive. In some cases, such as the one precipitating the present invention, one of the design features (the bellows) exceeded the factors of safety of the materials available.